| 摘要 |
Method and apparatus for testing an emergency shutdown valve without disrupting the flow of the process during a testing procedure. The apparatus includes an emergency shutdown valve capable of moving about 25% beyond a fully opened position to a fully closed position. The emergency shutdown valve has a coefficient of flow which is equal to or greater than the normal coefficient of flow for the process when the valve is moved about 25% beyond its fully opened position which provides a means for moving the shutdown valve 50% of its total movement without affecting the coefficient of flow for the process. The apparatus also includes a programmable logic controller including a timer and counter, a valve actuator, valve positioner, and an alarm device for controlling the positioning and movement of the shutdown valve during a timed and scheduled shutdown valve testing process without affecting the flow of the process.</PTEXT>
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